A great smartphone can really make you more productive. Your phone doesn't just keep you in contact with employees, colleagues and collaborators; it also helps you plan your workday, schedule meetings and stay productive all day long, even when you're away from the office. But with so many models to choose from, it can be tough to pick the right business phone. Read on for our list of the best smartphones to buy in 2015.

HTC One M8

The new HTC One M8 is one of the fastest business phones around. But what really makes it stand out is its premium metal design. Its sleek body is 90 percent metal, giving it a premium look and feel, especially compared with competing plastic phones such as the Samsung Galaxy S5. And the One M8's rounded corners and understated accent lines add a touch of sophistication that puts this phone on a par with Apple's iPhone in terms of visual appeal. Design aside, the HTC One M8 boasts a sharp 5-inch display and time-saving features such as Motion Launch, which lets you activate the display simply by tapping it twice. And it's one seriously speedy business phone; its quad-core processor helps it perform even better than the Galaxy S5. That means users can look forward to smooth multitasking during daily use.

Samsung Galaxy Note 4

Samsung's Galaxy Note 4 is an exceptional business phone with super-sharp 5.7-inch display and a powerful processor. Samsung's Note line of phablets are also the only smartphones in the U.S. that come with a built-in stylus. Just pull out the stylus from its slot — or hover the tip near the display and press the single button located on its side — to access the compact Action Menu, which lets you jump to one of five useful pen input applications for quick sketching and note-taking. The device also features a number of useful multitasking tools that will help you put that big screen to good use, including Multi Window, which lets you run two applications at the same time in a split-screen view. And the Note 4 is the first phone in the line to feature a fingerprint scanner, providing business users an extra security boost.

iPhone 6 / iPhone 6 Plus

Apple's new iPhone comes in two sizes, giving you all the perks of iOS, but with more screen space to work on. The iPhone 6 packs a 4.7-inch display, while the iPhone 6 Plus features a huge 5.5-inch screen. Screen size aside, the phones are nearly identical. Both dwarf the cramped 4-inch screen on previous versions, and both include Apple's new, blazing-fast A8 processor for faster performance and snappier multitasking. And both the iPhone 6 and iPhone 6 Plus retain the fingerprint scanner that helped make last year's iPhone 5s one of the most secure business phones around. The new iPhones will also launch with iOS 8, the latest version of Apple's mobile operating system, which is packed with handy new features for business users. The iPhone 6 Plus does have a few extra features that the iPhone 6 lacks, including a dual-pane mode that lets you navigate through your Mail and messaging apps more easily, as well as a larger battery.

Moto X (2014)

It has the same name as last year's version, but the updated Moto X has tons of new tricks up its sleeve. For starters, the phone sports a big 5.2-inch display that makes the 4.7-inch screen on the original Moto X look puny. That's a plus for business users who want a little extra screen real estate for serious work. The 2014 Moto X also offers an updated version of Motorola's always-listening voice commands: now you can use any spoken phrase you want to wake your phone up before issuing a command, even when the display is turned off. That means you can take a note, set a reminder or retrieve turn-by-turn directions, all hands-free. And, of course, the new Moto X provides a faster processor than last year's model. But the best part is that the device is pretty affordable compared with other flagship phones: just $99 with a two-year contract.

Samsung Galaxy S5

If Samsung's 5.7-inch Note 4 is too big for you to handle, the Galaxy S5 packs most of the same features into a smaller package. The device sports a super-sharp 5.1-inch display, and it's one of the fastest smartphones around. It's also one of the most secure, since it features a fingerprint scanner and supports Knox, a robust security suite developed by Samsung. Users can also expect good battery life, thanks to a beefy internal battery and the new Ultra Low Power Mode, which disables your phone's battery-sucking extras when it's about to run out of juice. And like other Samsung smartphones, the Galaxy S5 supports Multi Window mode, letting you run two apps on-screen at once in a split-screen view.

HTC One M8 for Windows

HTC's awkwardly named One M8 for Windows might be the best business phone that doesn't run Android or iOS. Instead, the device is powered by Microsoft's Windows Phone operating system, which has a few key features that hold benefits for business users. That includes native integration with Microsoft Office, ensuring you always have access to all your documents and spreadsheets from anywhere. The One M8 for Windows also supports Cortana, Microsoft's voice-activated personal assistant, which enables context-sensitive alerts, as well as voice commands that let you perform all sorts of actions hands-free, from taking notes to setting reminders. Software aside, the One M8 for Windows sports the same hardware as the original HTC One M8, which runs on Android. That includes a slick aluminum body, a sharp 5-inch display and a super-fast processor.

Motorola Droid Turbo

Motorola's Droid Turbo delivers fast performance and great battery life. The centerpiece of the device is its quad HD display, which is sharp, bright and more than big enough to work on. And it has a cutting-edge processor with 3GB of RAM, so business users can expect extremely fast performance. Motorola also packed in a bunch of handy software features, such as support for always-listening voice commands, so you can save a note or send a message without ever touching your phone. And while it's far from the prettiest Android device released this year, it's one of the more durable flagship phones you'll find.

Huawei Ascend Mate 2

If you're a power user who needs a phone with the longest battery life available, Huawei's Ascend Mate 2 is a great choice — if you can handle the device's bulk. The phone sports a monster 6.1-inch (15.5 centimeters) display, making it one of the largest smartphones available. That gives you tons of screen space to work on, even if it makes for a less portable device. It's also a relatively affordable phablet; you can buy it off contract for under $300, with no need to sign a costly two-year agreement through a major wireless carrier. But the real highlight might be the Ascend Mate 2's epic 15-hour battery life. No other smartphone currently offers that kind of longevity.

Editors Picks

Brett Nuckles

Brett Nuckles has been a working journalist since 2009. He got his start in local newspapers covering community news, local government, education and more before he joined the Business News Daily staff in 2013. He graduated from Ohio University, where he studied Journalism and English. Follow him on Twitter @BrettNuckles.